1. Field of the Invention
The present invention relates to heat exchange systems, and more particularly to powered heat exchangers, or heat pumps, conformed to extend within a chimney for effecting heat exchange between the interior and exterior ends thereof.
2. Description of the Prior Art
At the core of all human freedom is the convenience that one obtains through the assistance of external energy. Starting with fire, thereafter followed by the water wheel and all the other energy harnessing developments, this drive for freedom has served as the consistent forcing mechanism for most of our technological advancements. Recently, however, the phase lag between the efficiencies of energy use and the growth trends in the Earth's population have resulted in an exponentially increasing demand on all sources of energy and, of course, this increasing demand was then closely followed by exponential increases in energy price. This exponential energy cost burden, directly associated with population density increases, is now the principal constraint on the choices available to the energy user and has become the primary constraint on all human choices.
One reason for this narrowing of constraints is the inherent mismatch between the energy use efficiency of the devices currently assisting human activity and the exponential increase in energy price. For example, we have all grown accustomed in our past to the need of a fireplace, or a stove, and the ubiquitous chimney structure associated therewith that is now found in most residential buildings. At one time this inefficient mechanism for home heating was the prevailing standard which now provides a massive phase lag or inertia for any new development. Simply, the cost decisions involved in the design of a dwelling at an earlier time are wholly inapposite in the new constraints just a few years later. Nonetheless such phase lags persist and one aspect of all enlightened energy use development entails the convenience with which this existing architecture is adapted to the later developed use.
In the past various systems have been devised which in one way or another attempt to marry a heating or cooling device with a fireplace. Examples of such combinations can be found in the teachings of U.S. Pat. No. 4,132,263 issued to Stinnett; U.S. Pat. No. 4,126,118 to Haynes; U.S. Pat. No. 5,983,890 to Thomas, et al.; U.S. Pat. No. 5,775,408 to Shimek, et al.; U.S. Pat. No. 4 to Marelli; and others. While suitable for the purposes intended each of the foregoing focuses on the fireplace structure as the accommodation mechanism and does not utilize to full advantage the vertical gas column of the chimney associated therewith.
Those in the art will appreciate that the fundamentals of all thermodynamic exchange entail the fourth power of the temperature difference for radiative heat transfer and a third power effect for all convective transfer. Heat loss or gain is therefore exponentially related to temperature difference and the temperature difference between the gas column within a chimney and its ambient environment is the primary parameter for producing convective chimney drafts. Of course, this draft exists only with positive temperature differences as the fireplace-chimney mechanism is a development pre-dating the evolution of the compression-expansion cycle associated with reversible heat pumps. Efficient utilization of this earlier ubiquitous one-directional chimney mechanism with the high efficiency heat pumps that are now available is a matter of substantial focus and concern and it is one such combination that is disclosed herein.